Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 03, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	OLD DOMINION FREIGHT LINE INC/VA
Entity Central Index Key	0000878927
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q1
Trading Symbol	ODFL
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		82,199,387